For my son's ninth birthday party we had a sports day. We invited friends in various age groups and set up the entire yard with different sporting events.  We even set up a first aid station with band aid, bactine and a water cooler.  We divided the children up into age brackets, with events for the younger children (four and under) and other events for the children five years of age and up.  We bought ribbons for 1st through fourth places for each event.  Each event was given a start time on the invitation and parents were welcome to stay and join in on the fun. Since I had a few children that were not comfortable with staying without their parents, it was a natural way to have the parents hang out and participate in the fun. We had an adult at each sporting event, with a list of names for each participant. This allowed the person with the event to keep track of the statistics and make awarding the ribbons easier. The kids were also given treat bags and we busted a Basketball piñata.  Some of the events that we had included chicken limbo, balloon popping, basketball free throws, golf ball hitting (accuracy), three legged races, water balloons (to help cool them off) and football kick.  It was a perfect day for a bunch of boys that play various sports together and are always horsing around. It also kept the kids out of the house and allowed them to really enjoy themselves.  The party was three hours long and included pizza for lunch.  My son's birthday is in October, so we never know what the weather is going to be like.  The forecast turned out to be true, it was in the high 70's that day and made for a perfect outdoor activity for boys and girls.